The assembly of electronic components into functional circuits is carried out utilizing a broad variety of techniques, ranging from the hand positioning and soldering of components to a substrate such as a circuit board to the employment of automated, robotic assembly systems. While the latter automated systems may be highly efficient, such efficiency is realized only under very high volume production circumstances. Where unit volumes are lower, for example below batch unit numbers of about 10,000 circuit board units, practical production criteria generally dictates a return to semi-automatic or hand-assembly approaches.
Over the recent past, surface mounted circuit technology has been introduced. With this technology, component leads are not inserted through receiving holes formed within a circuit board or like substrate, but are fashioned to extend outwardly in parallel with the supporting circuit board surface. Correspondingly, the printed circuits supported by the circuit board are configured having sequences or patterns of surface mounting pads configured to mate in abutting contact with the short, outwardly-extending surface mount leads of the components.
Where production volumes dictate the use of hand assembly techniques for the surface mounted systems, numerous manipular complexities are imposed upon assembly personnel. Initially, the minutely-dimensioned surface mount leads must be aligned by eye with corresponding substrate pad patterns. Such alignment must be quite exacting. Following placement, the components must be physically retained in position, inasmuch as only a freely-abutting lead-pad association is developed. Typically, the component is glued to the circuit board at the time of placement and alignment. Following the gluing procedure, a circuit completing lead-pad union is formed utilizing wave-soldering or similar technology. Alternately, Re-Flow techniques may be employed wherein a Re-Flow solder is deposited upon the pads of the printed circuit board and the assembly of circuit board and circuit components is submitted to IR/convection, or vapor phase type connecting procedures. Because component leads are not inserted through circuit board receiving holes, the assurances or operator feedback that a proper component has been positioned at a correspondingly proper location within a forward mounted circuit often are not present with surface mount systems. In view of the foregoing, investigators have sought to develop a technique for providing practical, relatively lower volume assembly approaches for surface mounted type circuits wherein proper component selection and pad-lead alignment are assured and the otherwise intense labor requirements for assembling these systems are returned to more reasonable levels.